Power cylinder with piston return by own vacuum force

Claim 2

A hydraulic/pneumatic power cylinder for use with pressurized working fluid comprising: an elongated cylinder of tubular configuration, internally having a portion of smaller diameter with an end wall at one cylinder end forming one cylinder end blind, a shoulder approximately midway leading to another coaxial portion of larger diameter with an open end forming an opposite cylinder receiver end open and adaptable to be closed by a rod end closure, a fluid supply and exhaust port means in said cylinder blind end, a rod end closure including a central opening and mounted on said open end a coaxial piston and rod assembly with a differential diameter piston having a small diameter elongated piston at one end and a piston rod at the other end with a larger diameter short piston approximately midway thereof, said small elongated piston being in close sliding fit with said smaller diameter cylinder, said larger diameter short piston being in close sliding fit said larger cylinder, said piston rod being permanently secured to the face of said larger diameter piston centrally comprising a coaxial piston and rod assembly, said piston being slidably received in said elongated cylinder with the small diameter elongated piston entering the small diameter cylinder and the larger diameter short piston entering the larger diameter cylinder until it abuts and bottoms at said shoulder, seals on said small piston exposed to said cylinder blind end and on said larger diameter short piston, said piston rod protruding said cylinder open end when said larger diameter short piston is bottomed at said shoulder, said rod closure slidably accommodating said pis-ton rod, fastening means for securing said rod end closure within said cylinder open receiver end to close said cylinder and to serve as a piston stop when the piston is urged to axially move from a first piston rod retracted position to a se-cond piston rod extended position, venting means for admitting atmospheric pressure to the space between said larger piston and said rod end closure, said small and larger piston, said seals, said cylinder, and said shoulder defining an isolated and evacuated annulus when said piston rod is moved to extend axially therein to assume said second piston rod extended position, whereby a vacuum force is generated which force together with atmospheric pressure acting over the surface of larger piston and rod exposed thereto develops a sufficiently large combined force for piston rod return by its own vacuum force from the second piston rod extended position to the first piston rod retracted position, and whereby when said piston is in said piston rod extended position, said small piston end with said seal is engaged in said smaller diameter cylinder portion.

Claim 3

A hydraulic/pneumatic power cylinder for use with pressurized working fluid comprising: an elongated cylinder of tubular configuration internally having a portion of smaller diameter with an end wall at one cylinder end forming one cylinder end blind, a shoulder approximately midway leading to another coaxial portion of larger diameter with an open end forming an opposiee cylinder receiver end open and adaptable to be closed by a rod end closure, a fluid supply and exhaust port means in said cylinder blind end, a coaxial piston and rod assembly with small and large diameter pistons incorporated therein having a small diameter elongated piston at one end and a piston rod at the other end with a larger diameter short piston approximately midway thereof, said small elongated piston being in close sliding fit with said small diameter cylinder, and said larger diameter short piston being in close sliding fit with said larger cylinder, said piston rod permanently secured to the face of said larger diameter piston and located centrally to provide said coaxial piston and rod assembly, seals on said small and large pistons, said piston slidably received in said cylinder with the small diameter elongated piston entering the small diameter cylinder and the larger short diameter piston entering larger diameter cylinder for operating between a first piston rod retracted position and a second piston rod extended position, whereby when said piston is in the first retracted position, said larger diameter short piston abuts and bottoms said shoulder while said elongated small piston fully engages the small diameter cylinder portion thereby displacing all air from the space occupied by said piston, and when said piston is in the second extended position, an isolated and evacuated annulus is created between said smaller and larger pistons, said seals, said cylinder, and said shoulder when said larger piston moves axially away from said shoulder upon cylinder actuation by pressurized fluid entering fluid supply port means in said cylinder blind end, said evacuated annulus providing a vacuum force for piston return to the original first piston rod retracted position automatically when said pressurized fluid is allowed to escape from said cylinder blind end via said fluid exhaust port means, a rod receiving end closure secured in said cylinder open end including venting means for the space between the larger piston and the end end closure whereby when said short piston is moved from said first piston rod retracted position to said second piston rod extended position atmospheric air is displaced therefrom to facilitate proper operation of the cylinder and whereby when the cylinder blind end is allowed to exhaust, said atmospheric air returns thereto to act upon said larger diameter short piston and together with said vacuum force in said annulus to return said piston automatically to the original first piston rod retracted position, said second piston rod extended position being determined by the position of said rod end closure.

Claim 4

A hydraulic/pneumatic power cylinder for use with pressurized working fluid comprising: an elongated cylinder of tubular configuration internally having a portion of smaller diameter with an end wall at one cylinder end forming one cylinder end blind, a shoulder approximately midway leading to another coaxial portion of larger diameter with an open end forming an opposiee cylinder receiver end open and adaptable to be closed by a rod end closure, a fluid supply and exhaust port means in said cylinder blind end, a coaxial piston and rod assembly with small and large diameter pistons incorporated therein having a small diameter elongated piston at one end and a piston rod at the other end with a larger diameter short piston approximately midway thereof, said small elongated piston being in close sliding fit with said small diameter cylinder, and said larger diameter short piston being in close sliding fit with said larger cylinder, said piston rod permanently secured to the face of said larger diameter piston and located centrally to provide said coaxial piston and rod assembly, seals on said small and large pistons, said piston slidably received in said cylinder with the small diameter elongated piston entering the small diameter cylinder and the larger short diameter piston entering larger diameter cylinder for operating between a first piston rod retracted position and a second piston rod extended position, whereby when said piston is in the first retracted position, said larger diameter short piston abuts and bottoms said shoulder while said elongated small piston fully engages the small diameter cylinder portion thereby displacing all air from the space occupied by said piston, and when said piston is in the second extended position, an isolated and evacuated annulus is created between said smaller and larger pistons, said seals, said cylinder, and said shoulder when said larger piston moves axially away from said shoulder upon cylinder actuation by pressurized fluid entering fluid supply port means in said cylinder blind end, said evacuated annulus providing a vacuum force for piston return to the original first piston rod retracted position automatically when said pressurized fluid is allowed to escape from said cylinder blind end via said fluid exhaust port means, a rod receiving end closure secured in said cylinder open end including venting means for the space between the larger piston and the end end closure whereby when said short piston is moved from said first piston rod retracted position to said second piston rod extended position atmospheric air is displaced therefrom to facilitate proper operation of the cylinder and whereby when the cylinder blind end is allowed to exhaust, said atmospheric air returns thereto to act upon said larger diameter short piston and together with said vacuum force in said annulus to return said piston automatically to the original first piston rod retracted position, said second piston rod extended position being determined by the position of said rod end closure.

Claim 5

A cylinder as in claim 2 wherein said seals on said pistons are of U-cup configuration.

Claim 6

A cylinder as in claim 1 wherein said small piston end includes dual seals with seal venting means therebetween for exhaust to the atmosphere, said seal venting means including a passage initiating between said seals of said elongated smalll piston end by entering thereto radially to meet an axial passage provided therein communication with a passage in said piston rod leading to the atmosphere.

Claim 7

A cylinder as in claim 2 wherein all components are non-metallic.

Claim 8

A power cylinder with piston return by its own vacuum force comprising: a cylinder having shoulder defined between differential diameter portions, a piston having a shoulder defined between differential diameter portions, said piston in its retracted position being positioned within said cylinder with said respective differential diameter portions of said piston and cylinder being in close sliding fit and with the respective shoulders of said piston and cylinder abutting and bottoming on one another, seals on the differential diameter portions of said piston, a piston rod attached to the face of the larger diameter portion of said piston and protruding at one cylinder open end, a cylinder closure at another cylinder end adjacent said small diameter comprising a cylinder blind end, port means opening into a said cylinder at said blind end for supply and exhaust of the pressurized working fluid and adaptable for connecting a 3-way operating valve thereto to control the directional flow to and from the cylinder blind end during the cylinder operation, said cylinder operation including piston axial movement from a first piston rod retracted position to a second piston rod extended Position in response to the directional flow of pressurized fluid whereby when said fluid is allowed to enter said cylinder blind end via said port provided therein, said piston is moved to assume said second piston rod extended position, and when said fluid is allowed to exhaust therefrom via said port, said piston is moved to assume said first piston rod retracted position, said piston motion from said first to said second positions developing an isolated and evacuated annulus between said piston and cylinder, said seals, and said shoulders to produce a vacuum force large enough to return said piston from said second to said first positions when said cylinder blind end is open to exhaust.

Claim 9

A power cylinder with piston return by its own vacuum force comprising: a cylinder having shoulder defined between differential diameter portions, a piston having a shoulder defined between differential diameter portions, said piston in its retracted position being positioned within said cylinder with said respective differential diameter portions of said piston and cylinder being in close sliding fit and with the respective shoulders of said piston and cylinder abutting and bottoming on one another, seals on the differential diameter portions of said piston, a piston rod attached to the face of the larger diameter portion of said piston and protruding at one cylinder open end, a cylinder closure at another cylinder end adjacent said small diameter comprising a cylinder blind end, port means opening into a said cylinder at said blind end for supply and exhaust of the pressurized working fluid and adaptable for connecting a 3-way operating valve thereto to control the directional flow to and from the cylinder blind end during the cylinder operation, said cylinder operation including piston axial movement from a first piston rod retracted position to a second piston rod extended Position in response to the directional flow of pressurized fluid whereby when said fluid is allowed to enter said cylinder blind end via said port provided therein, said piston is moved to assume said second piston rod extended position, and when said fluid is allowed to exhaust therefrom via said port, said piston is moved to assume said first piston rod retracted position, said piston motion from said first to said second positions developing an isolated and evacuated annulus between said piston and cylinder, said seals, and said shoulders to produce a vacuum force large enough to return said piston from said second to said first positions when said cylinder blind end is open to exhaust.

Claim 10

A power cylinder with piston return by own vacuum force comprising: an elongated cylinder means having one cylinder end blind defined by an end wall and another cylinder end open, a rod end closure including a central opening connected by securement means to said open end, said cylinder means including internal diameter tubular portions of different coaxial diameters separated by a shoulder substantially midway thereof with the larger diameter portion initiating at the cylinder open end while the smaller diameter portion continues inwardly from said shoulder until it meets said blind end wall, a plastic differential diameter piston means including a coaxial piston rod attached thereto, said piston means having an elongated smaller diameter piston at one end and a short diameter larger piston with said rod at the other end slidably received inside said cylinder means with the small piston entering the smaller diameter cylinder portion in close sliding fit, and end face of the larger piston abutting and bottoming on said shoulder, and the larger piston entering the larger diameter cylinder postion in close sliding fit for axial movement within the cylinder limited by said rod end closure at one piston rod extended position and said cylinder shoulder seals on said smaller and larger diameter piston portions, said rod end closure opening receives said piston rod, fluid supply and exhaust means at said cylinder blind end, whereby upon actuation by pressurized working fluid entering said fluid supply and exhaust port means said piston means moves towards an extended position developing an isolated and evacuated annulus between said shoulder, said piston and cylinder portions, and said seals to produce a vacuum therein whereby upon exhausting pressurized working fluid through said supply and exhaust means said piston means is returned to a retracted position by the force of he vacuum.

Claim 11

A power cylinder with piston return by own vacuum force comprising: an elongated cylinder means having one cylinder end blind defined by an end wall and another cylinder end open, a rod end closure including a central opening connected by securement means to said open end, said cylinder means including internal diameter tubular portions of different coaxial diameters separated by a shoulder substantially midway thereof with the larger diameter portion initiating at the cylinder open end while the smaller diameter portion continues inwardly from said shoulder until it meets said blind end wall, a plastic differential diameter piston means including a coaxial piston rod attached thereto, said piston means having an elongated smaller diameter piston at one end and a short diameter larger piston with said rod at the other end slidably received inside said cylinder means with the small piston entering the smaller diameter cylinder portion in close sliding fit, and end face of the larger piston abutting and bottoming on said shoulder, and the larger piston entering the larger diameter cylinder postion in close sliding fit for axial movement within the cylinder limited by said rod end closure at one piston rod extended position and said cylinder shoulder seals on said smaller and larger diameter piston portions, said rod end closure opening receives said piston rod, fluid supply and exhaust means at said cylinder blind end, whereby upon actuation by pressurized working fluid entering said fluid supply and exhaust port means said piston means moves towards an extended position developing an isolated and evacuated annulus between said shoulder, said piston and cylinder portions, and said seals to produce a vacuum therein whereby upon exhausting pressurized working fluid through said supply and exhaust means said piston means is returned to a retracted position by the force of he vacuum.